Help I am really angry for absolutely no reason?

I'm female, 16 years old and I don't have any disoreders that I know of. I think I might be hypoglycemic though because I get really irratable and then when I eat I go back to normal, I know everyone gets like that. But this happens a lot and my dad had it when he was my age too, he was actually diagnosed I hav not. I am soooo angry right now at everything ad I mean everything and all I want to do is lie on the ground. I know that because I'm a teen Im supposedt get moodswings and all but right now I'm ready to kill someone and don't know why. Please help